clap 2.33.3 has incorrect MSRV due to bitflags 1.3 MSRV bump

[CosmicHorrorDev]

Please complete the following tasks

• I have searched the discussions
• I have searched the existing issues

Clap Version

2.33.3

Where?

bitflags/bitflags#255

What's wrong?

The README states that clap >=2.21 has an MSRV of 1.42, but the dependency on bitflags = "1.2" allows for v1.3 which bumps the requirement up to 1.46

How to fix?

Either pin the requirement for bitflags to 1.2.x, bump the MSRV, or work with bitflags to see if something else can be sorted out

[epage]

This is one of those complications from MSRV:

• imo the version constraint is correct and we shouldn't be overly constraining for the sake of MSRV.
• Other crates are allowed to advance their MSRV without it being a breaking change.
• However, the tools for supporting MSRV are still quite crude

The best I can offer at the moment is to use -Z minimal-versions or to patch the dependency.

[rfan-debug]

@epage I ran into the same error. Would you mind giving me an example how to patch the transitive dependency bitflags of clap? My rustc version is 1.42.0

I tried to use a patch as the following but it does not work.

[patch.crates-io]
clap = {git = "https://github.com/clap-rs/clap", tag = "v2.33.3"}